Iranian officials said 413 people had died in the country. Some soldiers and border guards were among the dead, the Iranian army’s commander-in-chief told the state news channel IRINN.

In Iraq nine people died, a Red Crescent spokesman told the BBC. A UN office in the country said more than 500 people were injured there, and the earthquake was felt in Irbil, Sulaimaniya, Kirkuk and Basra as well as the capital, Baghdad.

Landslides have made it harder for rescuers to reach those affected in rural areas, and there are fears a dam could burst after it was damaged by the earthquake. People living nearby have reportedly been asked to leave.

Why is Iran prone to earthquakes?

Iran is one of those regions of the world that is all too familiar with quakes, and has experienced some very big tremors in the past.

In general terms, the big driver here is the clash between the Arabia and Eurasia tectonic plates. The former is pushing north by a couple of centimetres a year.

In the south-east of the country, the Arabia plate is actually pushing under the Eurasia plate, but in the north-west these great slabs rub directly against each other. The Zagros mountains are a result of all this compression.

Early reports indicate the quake occurred on a thrust fault. This means the crust on one side of the break in the rocks is moved vertically up and over the other side – which fits exactly with this general picture.

Geological agencies now produce immediate bulletins on the likely expected casualties. This modelling work is based on factors such as the size of the quake, population density and what is known about local construction methods. It’s inexact work, but the first bulletins suggested this event could produce many hundreds of deaths and perhaps thousands of injured individuals.

Are you in the area? Have you been affected by the earthquake? If it’s safe to share your experiences then please email haveyoursay@bbc.co.uk with your stories.

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